My kids have loved Epcot since they were very young. We even designed a book about Epcot for them to expand upon the "kidcot" station stops...with more info about countries and use it to get the CM's to talk about there countries with my kids.
To Do: The Movies are a nice break, The Showcase Players in the UK, Off Kilter at Canada, Acrobats in China, play the drums in the African/coke area, Norway has the playground. Future World has the Innoventions East/West lots of stuff here...take the time to go slow. Test Track, Figment...the Kodak playground is fun, Soarin'....We go to Epcot all the time and can always spend hours...